Simplify the following expression: $k = \dfrac{p^2 - 5p + 4}{p - 4} $
Answer: First factor the polynomial in the numerator. $ p^2 - 5p + 4 = (p - 4)(p - 1) $ So we can rewrite the expression as: $k = \dfrac{(p - 4)(p - 1)}{p - 4} $ We can divide the numerator and denominator by $(p - 4)$ on condition that $p \neq 4$ Therefore $k = p - 1; p \neq 4$